COSMO-REA2 COSMO-DE (2 km)

Figure 1: HErZ reanalysis domains

High-Resolution Regional Reanalysis for Europe C. Ohlwein1, J. Keller3, S. Wahl1, A. Hense1, S. Crewell2, P. Friederichs1

1University of Bonn, Germany, 2University of Cologne, Germany, 3Deutscher Wetterdienst DWD, Germany

1. Strategic goals •  Hans-Ertel-Centre for Weather Research (HErZ)

•  Enhance scientific research and education at universities and DWD •  Virtual center: five self-organized research groups (TB)

•  Climate Monitoring Branch (HErZ-TB4) •  Strengthen DWD’s capabilities in

the assessment of the regional and local climate and its variability

Figure 3: Observed and simulated brightness temperature (10.8 µm) – COSMO-REA6 vs MSG

Figure 2: Process cycle of the 6-km regional reanalysis system (COSMO-REA6)

•  Evaluation framework for renalyses •  Multi-parameter evaluation •  Spatio-temporal processes •  Budgets of mass and energy •  Forward operators (RTTOV, PAMTRA)

•  Independent observations •  Soil moisture •  Temperature and precipitation (if retained) •  MSG brightness temperatures •  AMSU-B Microwave Humidity Sensor •  IWV from GNSS measurements •  Ceilometer measurements

2. Reanalysis System •  Development of a high-resolution, regional reanalysis

•  COSMO-REA6: 6 km (current status: 1995–2014) •  COSMO-REA2: 2 km (current status: 2007–2014)

•  Output interval (150 fields): 15 min (2D), 60 min (3D)

•  Data assimilation on the regional scale •  Operational nudging scheme: SYNOP, SHIP, PILOT,

TEMP, AIREP, AMDAR, ACARS,… •  Additional latent heat nudging (LHN) of RADAR on

the 2-km scale •  Towards ensemble data assimilation approaches

(UERRA)

3. Evaluation •  Added value with respect to dynamical

downscaling and/or spatial interpolation

•  Synthesis of heterogeneous observation networks

•  Physical consistency in space and time and between variables

•  Coherence with independent observations

Figure 4: Horizontal kinetic energy spectra for different reanalyses.

Corresponding Publication: Bollmeyer et al. (2015): Towards a high-resolution regional reanalysis for the European CORDEX domain. Quart. J. Roy. Meteor. Soc. 141 (686), 1-15

•  Establish an operational climate monitoring framework as new data product at DWD

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4. Interesting characteristics

•  Kinetic energy spectra •  More energy on smaller

scales for higher resolution

•  COSMO-REA2: good representation of k−5/3 spectrum

•  Effective resolution: HIRLAM ~ 130 km COSMO-REA6 ~ 50 km COSMO-REA2 ~ 14 km

•  Spatio-temporal precipitation patterns

Figure 5: Accumulated 24h-precipitation for different datasets over the Alps (June 21 2007)